1. Field of the Invention
The present invention relates to cellulase and a cellulase preparation containing the same, as well as a removal of nap of cellulose-containing fibers, a process for reducing cellulose-containing fibers and a process for decoloring denim-dyed cellulose-containing fibers by using the cellulase or cellulase preparation.
2. Background Art
Cellulose-containing fibers are treated with cellulase to give desired properties to those fibers. For example, in the fiber industry, treatment is performed using cellulase in order to improve the texture and appearance of cellulose-containing fibers, and to give the appearance of being stonewashed to denim-dyed cellulose-containing fibers.
In addition, Tencel, a reproduced cellulose fiber that is spun wood pulp-based cellulose dissolved in an organic solvent, has attracted attention in recent years due to properties such as high strength, water absorbing capacity and the like, and its manufacturing method which causes very little environmental contamination. However, since nap is produced during the manufacturing process of Tencel, Tencel has low product value as a fiber if left as is. Therefore, methods for removing nap formed during the manufacturing process by using cellulase have been proposed.
At present, cellulases primarily originating in Trichoderma species and Humicola species of wood-rotting fungi are used for treatment of cellulose-containing fibers. However, a large amount of cellulase is required under the present conditions to demonstrate the desired effect on the fibers.
It is likely that the cost of this processing would be able to be reduced, if it were possible to be able to improve the texture and appearance of cellulose-containing fibers, give the appearance of being stone-washed to denim-dyed cellulose-containing fibers, and remove nap from Tencel by using highly active cellulase in smaller amount than the conventional amount.
Furthermore, an example of a cellulase originating in Humicola, it is shown in WO 91/17243 (Japanese Patent Laid-Open Publication No. 5-509223) that the endoglucanase gene of 43 kD was isolated from Humicola insolens DSM1800 strain, and that its base sequence was determined.